The objective of this study was to explore whether it is possible to describe based on the International Classification of Functioning, Disability and Health (ICF) relevant aspects of functioning and disability affected in multiple sclerosis (MS) as well as environmental factors relevant to persons with MS. The specific aim was to identify most relevant 'Body functions', 'Body structures', 'Activities and participation', as well as 'Environmental factors' in patients with MS using the ICF. Additionally, different MS forms were compared with respect to the identified problems. A multi-centre study was conducted in an empirical cross-sectional design. Data from 205 individuals with MS were collected in rehabilitation centres: disease related data, socio-demographic data, single interviews based on the Extended ICF Checklist and a patient questionnaire including ratings on general health and functioning status, Beck Depression Inventory II (BDI-II) and Comorbidity Questionnaire (SCQ). The 129 ICF categories identified represent a comprehensive classification of functioning in MS from the clinical perspective. Differences between MS forms were observed for several ICF categories, EDSS, general health and functioning status, but not for BDI and SCQ. The study showed that it is possible to describe based on the ICF the spectrum in functioning and disability affected in MS as well as environmental factors relevant to persons with MS.